Optical disk device using a recording medium structurally arranged to generate a recording clock

ABSTRACT

A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of application Ser. No. 09/550,601,filed Apr. 17, 2000, which is a continuation of application Ser. No.09/011,486, filed Feb. 4, 1998, now U.S. Pat. No. 6,125,084, which is a371 of PCT/JP95/01585, filed Aug. 9, 1995, which is incorporated hereinby reference.

TECHNICAL FIELD

The present invention relates to an information recording/reproducingapparatus for recording or reproducing information on or from an opticalrecording medium, and more particularly to a method and an apparatus forrealizing high density recording/reproducing by applying a magneticfield modulation magnetooptical recording method to an optical disk.

BACKGROUND ART

A magnetic field modulation magnetooptical recording/reproducing methodhas been known conventionally as a technique of making an optical diskhighly dense.

As one example of conventional techniques, a consecutive light pulseirradiation and magnetic field modulation method described inJP-A-1-292603 and applied to an optical disk drive will be described.With this disk drive, clock signals are obtained from a preformattedclock pit train on an optical disk of a sample-servo format.

As shown in FIG. 8, while high output light pulses 802 synchronizingwith clock signals 801 are irradiated, modulation magnetic fields 808corresponding to data 803 are applied synchronously with the lightpulses 802 to form magnetic domains 804. During the reproduction, thedata 803 is detected by using the same clock signals 801. Thecharacteristic feature of this method resides in that the edge distance807 of the magnetic domain 805 recorded with too large a power is thesame as the edge distance 807 of the magnetic domain 804 recorded withtoo small a power, irrespective of their different recording powers. Itis therefore possible to record/reproduce always at a constant edgedistance 807 and is suitable for high bit density recording/reproducing.

A second conventional example as a means for solving a recording mediumsensitivity fluctuation problem associated with light modulation edgerecording will be described with reference to JP-A-4-61028. According tothe second conventional example, a recording medium is provided with atrial writing area at a predetermined position and a trial writingpattern is actually recorded in this trial writing area. By evaluating asignal reproduced from this trial area, optimization of a recordingpower level is performed.

FIG. 7 shows an example of the structure necessary for evaluating areproduction signal for the optimization of recording conditionsaccording to the second conventional example.

As shown in FIG. 7 at (a), a combination of two shortest/longestrecording mark/gap repetition patterns determined from a recordingmodulation method is used as a trial writing pattern. If a (1,7)modulation method is used as a coding method, the lengths ofshortest/longest recording mark/gap are 2 Tw and 8 Tw respectively (Twis a channel bit length, i.e., a shortest change length of a recordingmark, i.e., a detection window width). If the bit length of therecording code train is 0.53 microns, the longest mark/gap length is 3.0microns. If the laser wavelength is 780 nm and the lens NA is 0.55, theamplitude of a signal reproduced from the repetition pattern(hereinafter called “coarsest pattern”) of the longest recordingmark/gap (each 8 Tw long) is generally determined only by the width ofthe recording mark, and the positions of leading and trailing edges of asignal correspond to the edge positions. On the other hand, theamplitude of a signal reproduced from the repetition pattern(hereinafter called “densest pattern”) of the shortest recordingmark/gap (each 2 Tw long) is smaller than the coarsest pattern becausethe recording mark/gap length is generally equal to a half the diameterof the reproduction light spot. The center level of the reproductionsignal amplitude shifts toward the recording mark because of opticalinterference of the preceding and succeeding recording marks. This shiftamount is influenced by both the length and width of the recording mark.The longer and wider the recording mark, the larger the shift amount.From the above consideration, the recording control has been performedso that the width of the recording mark becomes generally constantirrespective of the recording mark length, and the recording power levelhas been optimized by making the amplitude center level determined bythe recording mark/gap (e.g., coarsest pattern) sufficiently longer thanthe diameter of the reproduction light spot become coincident with thereproduction signal center level of the densest pattern.

In the structure shown in FIG. 7 at (d) and disclosed in the above-citedpublication, the center level of the amplitude of a signal reproducedfrom the densest/coarsest pattern is obtained as an average value ofsignal levels representative of the upper and lower envelopes. The peakand bottom levels of the reproduction signal 701 of the densest patternare held by peak and bottom holding circuits 704 and 705, and theaverage level of the peak and bottom levels is held by a sample-holdcircuit 707 by using a densest pattern detection gate 702 as a trigger.Similarly, the average level of a reproduction signal of the coarsestpattern is held by a sample-hold circuit 706 by using a coarsest patterndetection gate 703 as a trigger. A difference (V1−V2) between the twoaverage levels is calculated by a differential amplifier circuit 708 toobtain a reproduction signal evaluation result signal 713 (ΔV signal:ΔV=V1−V2). The center level of a signal reproduced from the coarsestpattern changes scarcely even if the recording conditions shift more orless from the optimum conditions and recording mark/gap lengths areunbalanced more or less.

The structure shown in FIG. 7 at (e) is also disclosed in theabove-cited publication as a method of evaluating the recordingconditions from a reproduction signal. By using a low-pass filter 709having a cut-off frequency lower than the frequency of a reproductionsignal of the coarsest pattern, signal levels of the densest/coarsestpatterns are sampled and held to form a reproduction signal evaluationresult signal 714 (ΔV signal). The recording power has been optimized bysetting the recording power level so that ΔV becomes 0. In this manner,recording can be performed always with generally a constant magneticdomain width.

FIG. 9 is a flow chart illustrating a basic sequence of the recordingcondition optimizing operation of the second conventional example. Inthis example, it is assumed that the recording medium is an optical diskand the trial writing pattern is a densest/coarsest pattern. When therecording condition optimizing operation starts, a trial writing areaprovided on a recording medium at a predetermined position is erased toprepare for the next writing operation. As the writing operation starts,a predetermined writing pattern is recorded on the recording mediumunder different recording conditions for each recording area (e.g.,sector) which is the unit of recording management of the recordingmedium. After the recording operation is finished, the reproductionsignal of each recording area is evaluated to determine the recordingconditions most suitable for the optimum recording conditions. Since therecording conditions are different in the radial direction of therecording medium, the above recording operation is performed at properradial positions of the recording medium (e.g., inner circumferentialarea, middle circumferential area, outer circumferential area, or eachrecording zone) to complete the trial writing operation.

DISCLOSURE OF INVENTION

High speed and high integration of external storage devices or the likeof computers have been long desired. As described with the related art,the magnetic field modulation magnetooptic recording method with lightpulse irradiation is expected greatly because it allows overwrite and abit density is high. Furthermore, this method has the characteristicsthat an edge distance of a magnetic domain does not change and thereproduction signal waveform is not affected, even if a recording powerchanges.

This method is, however, associated with the problem that it isdifficult to detect that the width of a magnetic domain becomes toobroad by applying an excessive power, because the reproduction signal istoo stable. This becomes a serious issue preventing the improvement of atrack density. Even if the trial writing operation is performed by themethod of the second conventional example, the reproduction signalevaluation result signal (? V signal) will not change in principle. Itis therefore impossible to record a magnetic domain with a precisewidth. If the trial writing operation is performed with an excessivepower in particular, data on adjacent tracks may be destroyed. In orderto avoid destroying data on adjacent tracks, it is essential to reservea sufficient track width, so that high density cannot be expected.Another problem is medium compatibility that the driver cannot determinean optimum power of a medium having a different recording sensitivity.

As above, conventional magnetic field modulation recording methods areassociated with the problem that they cannot improve the track densitysufficiently and with the problem of medium compatibility.

An object of the present invention is to improve the area recordingdensity by narrowing the recording mark width to have narrow tracks andto suppress a recording reproduction variation betweenrecording/reproducing apparatuses.

The above object can be achieved by performing a trial writing operationof data in a predetermined area of a recording medium by a methoddifferent from a normal information recording, adjusting the light pulseoutput in accordance with the domain size information obtained by thetrial writing operation, and after confirming the adaptability betweenthe recording medium and a recording/reproducing apparatus, startingrecording ordinary data.

In recording/reproducing by an optical information recording/reproducingapparatus, a trial writing operation is performed by a recording methodproviding a high detection sensitivity of a magnetic domain size orrecording mark size, and in accordance with the results of the trialwriting operation, normal information recording is performed. It becomespossible, therefore, to precisely control the magnetic domain size orrecording mark size and the width of the magnetic domain or recordingmark. In this manner, the recording density of an optical informationrecording/reproducing apparatus can be improved greatly.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the structure of a drive according tothe invention,

FIG. 2 shows waveforms of a record control circuit of this invention,

FIG. 3 is a circuit diagram of a laser drive circuit of the invention,

FIG. 4 is a conceptual diagram illustrating a trial writing method ofthe invention,

FIG. 5 is a conceptual diagram illustrating how an optimized recordstate is found according to the invention,

FIG. 6 is a conceptual diagram showing an example of a trial writingoperation of the invention,

FIG. 7 shows waveforms illustrating a conventional example of a trialwriting method,

FIG. 8 is a conceptual diagram showing an example of light pulsemodulation magnetic field modulation,

FIG. 9 is a flow chart illustrating a trial writing operation sequence,and

FIG. 10 is a conceptual diagram illustrating a simplified trial writingoperation.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the invention will be described hereinunder.

FIG. 1 is a block diagram showing an example of the structure of a driveaccording to the invention. An optical head 100 focusses a laser beamirradiated from a laser 101 onto a recording medium (optical disk) 102.The recording medium 102 is not limited only to a disk, but it may be atape, a card or the like to realize the same embodiment configuration.The laser beam reflected from the recording medium 102 is introducedinto a photodetector 103 and converted into various electrical signalsby known techniques. Of these electrical signals, a servo signal 104 issupplied to a servo control circuit 105, a pit signal 106 is supplied toa timing generating circuit 107, and a magnetooptic data signal 108 issupplied to an A/D conversion circuit 109.

A servo clock 110 generated by the timing generating circuit 107 inaccordance with the pit signal 106 is supplied, together with the servosignal 104, to a servo control circuit 105 which in turn generates anactuator control signal 111. The actuator control signal 111 is suppliedto a spot positioning actuator 112 to position a light spot on therecording medium 102.

During a normal information reproduction, the A/D conversion circuit 109digitizes the magnetooptical data signal 108 at the timing of areproduction clock 113 generated by the timing generating circuit 107,to thereby output a digitized reproduction signal 114. The digitizedreproduction signal 114 is converted by a data discriminating circuitinto a reproduction signal which is output to an interface circuit 117.

During a normal information reproduction, the A/D conversion circuit 109digitizes the magnetooptical data signal 108 at the timing of areproduction clock 13 generated by the timing generating circuit 107, tothereby output a digitized reproduction signal 114. The digitizedreproduction signal 114 is converted by a data discriminating circuit115 into a reproduction signal which is output to an interface circuit117.

Under these conditions, the interface circuit 117 supplies recordingdata 124 to the recording control circuit 122 which in turn outputs amagnetic head control signal 126 and a laser control signal 127synchronizing with a recording clock 125. The laser control signal 127is a signal representative of a consecutive pulse train with a constantperiod and of a power, both synchronizing with the recording clock 125.The magnetic head control signal 126 is a signal representative of therecording data 124 delayed to make its phase coincident with that of thelaser control signal 127. As a result, the magnetic head 132 and laser101 output light pulses 802 and modulation magnetic fields 808 suchshown in FIG. 8.

The outline of the operation of a trial writing mode of the driveaccording to the invention will be described. As the drive isinitialized upon turning on a drive power or the like, the centralcontrol circuit 18 first checks whether a recording medium 102 is set inthe drive. If not, the operation stands by, whereas if set, the centralcontrol circuit 118 performs a recording optimizing operation in orderto confirm adaptability between the recording medium 102 and drive. Theoperation of the drive will be specifically described hereinafter. Whena light spot is positioned in a specific trial writing area of therecording medium, in response to the pit signal 106 the timinggenerating circuit 107 supplies the disk area signal 119 to the centralcontrol circuit 118 to notify that the light spot is positioned in thetrial writing area. Upon reception of the disk area signal 119, thecentral control circuit 118 sends the recording mode signal 120indicating the trial writing mode to the recording control circuit 122.

Upon reception of the recording mode signal 120, the recording controlcircuit 122 starts a recording operation by using data in a trialwriting data ROM 128, not by using the recording data 124 from theinterface circuit 117 as in the normal recording. The trial writing dataROM 128 stores therein consecutive “0s” data and recording conditionoptimizing data (trial writing pattern). First, in accordance with theconsecutive “0s” data, the recording control circuit 122 outputs themagnetic head control signal 126 for applying a magnetic field in theerase direction and the laser control signal 127 for irradiatingconsecutive pulse light. In accordance with the magnetic head controlsignal 126 and laser control signal 127, the magnetic head drivercircuit 130 and laser driver circuit 131 perform a trial writing areaerase operation.

If some recording magnetic domains are left unerased because of aninsufficient laser power, the erase operation is performed not only onthe subject track but also on the intermediate area between adjacenttracks, through tracking servo, in order to ensure a perfect erasestate.

The recording condition optimizing operation then starts for the trialwriting area with recording magnetic domains being erased, by outputtingthe recording condition optimizing data (trial writing pattern) 129 fromthe trial writing data ROM 128. In this recording condition optimizingoperation, the central control circuit 118 operates to actually write apredetermined digitized trial writing pattern to be described later, anddetermines the optimum writing conditions in accordance with theevaluation results of a digitized reproduction signal 114 reproducedfrom the recording pattern. The recording condition optimizing operationis performed at a proper time interval and when the recording medium 102is exchanged. With this combination of recording condition optimizingoperations, magnetic domains having generally a constant width can bestably formed and the reliability of the drive can be improved.

A simple method of determining the optimum recording conditions will bedescribed with reference to FIG. 10. While high output light pulses 154synchronizing with clock signals 151 generated from a pre-pit train areirradiated, modulation magnetic fields 153 corresponding to data 152 areapplied synchronously with the light pulses 154 to form magnetic domains155 to 157. In this case, consecutive “0s” and “1” in the data 152 areset sufficiently long.

From the magnetic domains 155 to 157 recorded by trial writing,magnetooptic data signals 165 to 167 are reproduced which are A/Dconverted synchronously with reproduction clock signals 158 to obtainportions of digitized reproduction signals 114, including V11, V12, V13,V14, V15, V16, and V17. These signal portions are classified into anerase level V11, transition levels V12 to V14, and recording levels V15to V17. As the recording power changes and the magnetic domain edgesshift, the transition levels greatly change among V12 to V14. Incontrast, the recording levels V15 to V17 change less. The erase leveland the recording level are required to take a saturated level. It istherefore necessary to set each trial writing pattern sufficientlylonger than a light spot diameter.

The central control circuit 118 receives V11 to V17 of the digitizedreproduction signals 114, and calculates a value of (transitionlevel−erase level)/(recording level−erase level). Based upon thecalculated value of (transition level−erase level)/(recordinglevel−erase level), the central control circuit 118 can estimate thesize of each magnetic domain recorded by trial writing.

The value of (transition level−erase level)/(recording level−eraselevel) takes a number larger than 0 and smaller than 1. For example, inthe example shown in FIG. 10, the target value of (transitionlevel−erase level)/(recording level−erase level) for a target magneticdomain size is about 0.5. The central control circuit 118 performs thetrial writing while scanning the recording power 408, and selects as theoptimum recording power the recording power used when the value of(transition level−erase level)/(recording level−erase level) calculatedfrom the reproduction signals becomes most nearest to 0.5. Since thevalue of (transition level−erase level)/(recording level−erase level) isaffected by a shift of the clock signals 153 and 158, these clocksignals 153 and 158 are required to be stable.

In the above manner, the recording conditions of forming magneticdomains (recording marks) having generally a constant width can be foundby the simple method illustrated in FIG. 10.

A more precise trial writing method will be described with reference toFIGS. 2 and 3. In the following, the operations in the trial writingmode of the recording control circuit 122 and laser driver circuit 131shown in FIG. 1 will be described. After the erase operation for thetrial writing area, the recording control circuit 128 performs arecording operation by using the data (trial writing data) 129 stored inthe trial writing data ROM 128. If the recording medium 102 has a narrowtrack pitch, a trial writing is controlled so as not to write the dataon nearest adjacent tracks of the subject track, so that themagnetooptic data signals 108 on the trial written subject track willnot interfere with each other.

FIG. 2 shows examples of recording clocks 125 and data 129. The data 129is delayed by one clock to form delay data 201. A gate is opened duringtwo clocks after the trailing edge timing 202 of the delay data 201 toform a gate signal 203. The gate signal 203 is inverted to form aninverted gate signal 204. An AND operation is performed between theinverted gate signal 204 and recording clocks 125 to form recordingpulses 205.

The gate signal 203 is used as an auxiliary recording pulse 301 shown inFIG. 3. The recording power signal 121 supplied from the central controlcircuit 118 is halved to form an auxiliary recording power signal 302.The recording control circuit 122 supplies the recording pulse 205,recording power signal 121, auxiliary recording pulse 301 and auxiliaryrecording power signal 302 to the laser driver circuit 131, as the lasercontrol signal 127. The recording power signal 121 and auxiliaryrecording power signal 302 are input to constant current circuits 304and 305, respectively, to set current value I2 and I3. The constantcurrent circuit 303 flows a reproduction bias current I1 in a steadymanner. The recording pulse 205 and auxiliary recording pulse 301operate to open and close current switches 306 and 307, respectively, sothat the laser 101 irradiates light pulses 206 shown in FIG. 2. Therecording control circuit 122 delays the data 120, while taking a delayin the magnetic head driver circuit 130 into consideration, to form themagnetic head control signal 126 which is input to the magnetic headdriver circuit 130 to generate the modulation magnetic field 207 fromthe magnetic head 132.

With reference to FIG. 4, the shape 401 of a magnetic domain formed uponapplication of the light pulse 206 and modulation magnetic field 207will be described.

Immediately after a recording pulse 402, an auxiliary recording pulse403 is introduced which does not raise the medium temperature to therecording temperature and is not directly relevant to recording. Withthe introduction of this auxiliary recording pulse 403, a bipolarmagnetic domain 404 having an edge shape of an opposite curvature 406 tothe polarity 405 in the normal recording can be recorded. Although theauxiliary recording power may be 0, a good balance is ensured if theauxiliary recording power 407 is set to a half the recording power 408.Namely, since the pulse width of one bit of the auxiliary recordingpulse 403 is a twofold of the pulse width of one bit of the recordingpulse 402 and since the auxiliary recording power 407 is a half therecording power 409, the light energy amount of one bit of the auxiliaryrecording pulse 403 can be set equal to that of one bit of the recordingpulse 402. Since a peak temperature by one light pulse is differentbetween the auxiliary recording pulse and the recording pulse, only therecording pulse 402 forms a magnetic domain. However, both the recordingpulse 402 and the auxiliary recording pulse 403 have the same thermalinfluence to the following recording area on the track. Accordingly, themagnetic domain size by one recording pulse is always maintained equalto the normal recording.

In the example shown in FIG. 4, a magnetic domain 409 in the erasedirection indicated by a while circle is formed by the recording pulse402 immediately before the bipolar magnetic domain 404. Therefore, evenif there is a difference in a strict sense between the thermal influenceof the auxiliary recording pulse 403 and the thermal influence of therecording pulse 402, this thermal influence difference can be reducedconsiderably. The magnetic domain shape 401 formed in the above mannerhas the characteristics that the magnetic domain width W is the same asthat of the normal recording although a different recording method isapplied, and that only the edge distance of the magnetic domain changeswith the recording power 408. The magnetic domain shape 411 with toolarge a recording power and the magnetic domain shape 412 with too smalla recording power are shown in the lower portion of FIG. 4.

With reference to FIG. 5, how the optimum recording conditions are foundwill be described. A magnetooptic data signal 503 shown in FIG. 5 isreproduced from magnetic domains 501 recorded by the trial writing.Attention is drawn to signals V1, V2, V3, V4, V5, V6, V7 and V8 amongdigitized reproduction signals 114 A/D converted from the magnetoopticdata signal 503 at reproduction clocks 502. The central control circuit118 receives V1 to V8 of the digitized reproduction signals 114 andcalculates the following values, including an average level A(V1+V2+V3+V4)/4 of bipolar magnetic domains 404, a level B=(V5+V6)/2 ofconsecutive gaps 504, and a level C=(V7+V8)/2 of consecutive magneticdomains 505. In accordance with the calculated value (C−A)/(C−B), thecentral control circuit 118 can estimate a size 506 of the magneticdomain recorded by the trial writing.

The value (C−A)/(C−B) is larger than 0 and smaller than 1. For example,assuming that the target value of (C−A)/(C−B) for the target magneticdomain size 506 is 0.5, the central control circuit 118 selects as theoptimum recording power the recording power used when the value of(C−A)/(C−B) calculated from the reproduction results of the trialwriting pattern recorded while scanning the recording power 408 becomesmost nearest to 0.5. If the magnetic domain width W is desired to be setsmall, the target value of (C−A)/(C−B) is set small, whereas if themagnetic domain width W is desired to be set large, the target value of(C−A)/(C−B) is set large.

If a domain shift level D=(V1−V2+V3−V4)/2 and a value of D/(C=B) arecalculated, it is possible to detect a shift of a recorded magneticdomain position from the timing of the reproduction clock 502. A shiftbetween the timing of the reproduction clock 502 and the recordedmagnetic domain position is an absolute position shift of the center ofa magnetic domain on the recording medium 102. Therefore, if theabsolute position shift poses some problem, the conditions of obtaininga constant or minimum value of D/(C−B) are selected by the trialwriting.

The bipolar magnetic domain 404 in this embodiment is recorded by asingle pulse. The bipolar magnetic domain 404 may be recorded by using atrain of a plurality of pulses. The bipolar magnetic domain 404 may berecorded in an isolated state from other magnetic domains. A necessarypoint for high precision trial writing is to record the bipolar magneticdomain 404 having edges of both positive and negative polarities in themoving direction of a light spot as in the case of magnetic domainsrecorded by a light modulation recording method. In addition to thedetection of the consecutive magnetic domain level C and consecutive gaplevel B, the necessary point during the reproduction is to detect theaverage level A of the bipolar magnetic domains 404 in such a mannerthat the magnetooptic data signal 503 is picked up at the timing of thereproduction clock 502 when the light spot comes near to the edges 405and 406 of positive and negative polarities. The information of therecorded magnetic domain size 506 can also be obtained if themagnetooptic data signal 503 can be picked up synchronously with thetiming of the reproduction clock 502 even when about a half area of thelight spot covers the edge of the opposite polarity 406.

Other examples are shown in FIG. 6. In these examples, the trial writingis performed solely by light modulation and the recording waveformsshown in FIG. 6 are used. In these examples, however, the target valueof (C−A)/(C−B) should be set carefully. For example, magnetic domains606 recorded by a modulation magnetic field 604 and light pulses 605have the same magnetic domain size because of recording correction.Therefore, similar to the case shown in FIG. 5, the target value of(C−A)/(C−B) is set to about 0.5. In the case of magnetic domains 603recorded by a modulation magnetic field 601 and light pulses 602, sincethe size of bipolar polarity magnetic domains 607 is small, it isnecessary to set the target value of (C−A)/(C−B) smaller.

As described so far, magnetic domains having an edge shape of acurvature opposite to that in the normal recording are trial recorded sothat magnetic domains (recording marks) having a constant width and acontrolled shape can be formed stably and with a high precision, on arecording medium. Accordingly, even if the track pitch of the recordingmedium 102 is narrowed, the reliability of recording/reproducing can beretained.

Industrial Applicability

According to the present invention, it is possible to suppress arecording sensitivity variation of recording media to be caused by adifference of suppliers, film thickness differences, or environmentaltemperature changes, to suppress a recording sensitivity variation ofrecording/reproducing apparatuses, to improve the adaptability betweenrecording/reproducing apparatuses and recording media, to controlrecording marks with a high precision, and to improve the reliabilityand storage capacity of recording/reproducing apparatuses.

What is claimed is:
 1. An optical disk drive for recording informationon a recording medium by forming optical recording marks, comprising: atiming generating circuit which generates a recording clock based on anelectrical signal obtained by converting a reflected beam from saidrecording medium; a light source which irradiates a light pulse on aspecific trial writing area of said recording medium in synchronizationwith said recording clock; a recording circuit which records a trialwriting pattern in said specific trial writing area of said recordingmedium in synchronism with said recording clock; a reproducing circuitwhich reproduces the trial writing pattern from the reflected beams fromsaid recording medium in accordance with said recording clock; and acontrolling circuit which determines conditions to form said opticalrecording marks in accordance with a transition level of reproductionsignals by said trial writing pattern.
 2. An optical disk driveaccording to claim 1, further comprising an erasing circuit which erasesdata on a track to be used for the recording of the trial writingpattern and on tracks which are adjacent to said track, prior to therecording of the trial writing pattern.
 3. An optical disk driveaccording to claim 1, further comprising means for enabling recording arecording pattern not appearing in a data area in said specific trialwriting area of said recording medium.
 4. An optical disk driveaccording to claim 1, further comprising means for picking up saidtransition level of reproduction signals by said trial writing pattern.5. An optical disk drive for recording information on a recording mediumby forming optical recording marks, comprising: a timing generatingcircuit which generates a recording clock based on an electrical signalobtained by converting a reflected beam from said recording medium; alight source which irradiates a light pulse on a specific trial writingarea of said recording medium in synchronization with said recordingclock, said specific trial writing area having a pattern longer than alight spot diameter; a recording circuit which records a trial writingpattern in said specific trial writing area of said recording medium insynchronism with said recording clock; a reproducing circuit whichreproduces the trial writing pattern from the reflected beam from saidrecording medium in accordance with said recording clock; and acontrolling circuit which controls a recording power of the light pulsein accordance with an output of said reproducing circuit.
 6. An opticaldisk drive according to claim 5, further comprising an erasing circuitwhich erases data on a track to be used for the recording of the trialwriting pattern and on tracks which adjacent to said track, prior torecording the trial writing pattern.
 7. An optical disk drive accordingto claim 5, further comprising means for recording a recording patternnot appearing in a data area, in said specific trial writing area ofsaid recording medium.
 8. An optical disk drive for recordinginformation on a recording medium by forming optical recording marks,comprising: a timing generating circuit which generates a recordingclock based on an electrical signal obtained by converting a reflectedbeam from said recording medium; a light source which irradiates a lightpulse on an area of said recording medium in synchronism with saidrecording clock; a recording circuit which records information in saidarea of said recording medium with said light pulse in synchronism withsaid recording clock.
 9. An optical disk drive according to claim 8,further comprising an erasing circuit which erases data on a track to beused for the recording of the trial writing pattern and on tracks whichare adjacent to said track, prior to the recording of the trial writingpattern.
 10. An optical disk drive according to claim 8, furthercomprising means for enabling recording a recording pattern notappearing in a data area in said specific trial writing area of saidrecording medium.
 11. An optical disk drive according to claim 8,further comprising means for picking up said transition level ofreproduction signals by said trial writing pattern.